Radio interference elimination choke for suppressing impulse like interference voltages

ABSTRACT

A radio interference elimination choke employs a magnetic impedance core having at least two annular axially superposed partial cores housed in an insulating omnilaterally closed cup upon which at least one winding is provided for attenuation of impulse-like interference voltages and build-up interferences in the low frequency range wherein at least one of the partial cores exhibits high losses in the frequency range of the build-up process.

United States Patent Kirmis et al. Dec. 25, 1973 [54] RADIO INTERFERENCE ELIMINATION 3,423,710 1/1969 Allen 336/212 X CHOKE FOR SUPPRESSING IMPULSE LIKE ga t ema INTERFERENCE VOLTAGES 2,988,715 6/1961 Gizynski et al. 336/96 [75] Inventors: Peter Kirmis; Heinz Wagner; 1,935,885 11/1933 Meissner 336/96 X Hans-Peter Kaiserswerth, all of Clemons X Regensburg, Germany 1,748,857 2/1930 Wellings et al. 336/155 x [73] Assignee: Siemens Aktiengesellschaft, Berlin FOREIGN PATENTS OR APPLICATIONS and Munich, Germany 1,804,835 8/1970 Gennany 336/212 28,423 3 1956 G 336 212 22 Filed: Nov. 24, 1971 I many [21] Appl. No.: 201,754 Primary Examiner-Thomas J. Kozma Attorney-Carlton Hill et al.

[30] Foreign Application Priority Data Nov. 27, 1970 Germany P 20 58 509.5 [57] ABSTRACT A radio interference elimination choke employs a [52] us. Cl 336/96, 336/189, 336/212, g i imp n r h ing at least two annular 335/229 336/233 axially superposed partial cores housed in an insulat- 51 1111.01. 11011 27/24 'g omnilaterally closed p p which at least one [58] Field of Search 336/96, 212, 233, winding is provided r n a ion of impulse-like in- 336/234 192 155 193 229, 189 terference voltages and build-up interferences in the low frequency range wherein at least one of the partial [56] R f n Cit d cores exhibits high losses in the frequency range of the UNITED STATES PATENTS bullddlp Pmcess- 2,843,683 7/1958 Lewis, Jr 336/l89 X 10 Claims, 2 Drawing Figures PATENT H] BEE 2 5 I975 SHEET 2 [IF 2 RADIO INTERFERENCE ELllMINATION CHOKE FOR SUPPRESSHNG IMPULSE LHKE IINTERFERENCE VOLTAGES BACKGROUND OF THE INVENTION 1. Field of-the Invention This invention relates to a radio interference elimination choke comprising an impedance core composed of different core materials, which core attenuates, in particular, impulse-like interference voltages which are caused, for example, in firing angle control circuits.

2. Description of the Prior Art Various radio interference elimination chokes having composite cores are well known in the art. These impedances use materials which exhibit losses which are as low as possible and supplement each other in their frequency amplitudes so that the impedances thereof act as transformers over as broad a band as possible. For this purpose, thin metal sheets which are well insulated from each other and constructed of different shapes and made from different material, including ferrite material, are superposed as the core structure.

In order to attenuate impulse-like interference voltages, coils having band ring cores of two supercoiled partial cores have been proposed in the German Utility Model Pat. No. 6,802,306. These cores contain precious and expensive alloys, but have the disadvantage of exhibiting, in spite of the precious alloys, a relatively high nonlinear distortion factor which disadvantageously reduces the attenuation of impulse-like interferences which contain a broad spectrum of frequencles.

SUMMARY OF THE lNVENTlON The primary object of the present invention is to create a low-cost choke component for the attenuation of impulse-like interferences as they occur, for example, in firing angle control circuits with thyristors.

It is also an object of the invention to provide a component of the type described which may be constructed in various sizes and at different costs for use in semiconductor circuits for commercial and industrial electronics, i.e., ventilators, speed adjustors, brightness controls, with a power draw of up to about 500 watts and capable'of reducing the interference voltages developed in such circuits below an interference degree N according to VDE (Association of German Engineers) 0875 without changing the control range of such circuits.

According to the invention, the foregoing objectives are achieved through the provision of a radio frequency interference elimination choke having a magnetic impedance core of at least two annular axially superposed partial cores and which is characterized in that for attenuation of impulse-like interference voltages and of transients in the low frequency range, at least one of the partial cores exhibits high losses in the frequency range of the transients.

Magnetic materials having high losses in the low frequency range precisely attenuate the undesirable transients of the interference suppression circuit which are stimulated, for example, by the operation of a firing angle control circuit, and which reduce the momentary value of the charge current below the hold current of an associated thyristor, thus being able to render the thyristor non-conductive. Moreover, the magnetic materials offer the advantage of a marked savings in cost with respect to the high cost of materials heretofore employed. The annular core shape offers, over all other core shapes, i.e., elliptical, U or E-shape, with small air gaps, the advantages obtained by a particularly favorable ratio of core losses to core volume.

In a further improvement of the invention, a choke device was developed to attenuate transients in the frequency range of5 to 15 kHz, whereby a partial core is composed of iron sheet metal containing Si. For increasing the permeability, particularly in the frequency range up to 10 MHz, at least one additional partial core is designed as a ferrite core with a permeability of at least 200, whereby the impedance core exhibits high losses due to the effect of the ferrite material in the frequency range from 10 to 300 MHz with a permeability which decreases with increasing frequency. This core structure, according to the invention, represents a combination of two attenuation principles: On the one hand, conversion of oscillating energy into heat by high losses in particularly critical frequency ranges; and on the other hand, attenuation of high frequency interferences by a relatively high inductive resistance in the high frequency range. Therefore, a uniform radio interference suppression can be accomplished in the entire desired rangeat a minimum cost and at a minimum space requirement. Such an impedance core comprises a first partial core which consists of rings of a coldrolled iron sheet containing 2.9 to 3.1%, preferably 3.0% silicon, and a second partial core which consists of a ferrite composed of 47.55 mole Fe,o,,, 3l.6 mole ZnO, 20.6 mole NiO and 0.25 mole C00, which may be produced according to well known con- 'ventional methods, and wherein the first partial core accounts for 65 to percent, preferably 67 percent, of the effective cross-section of the impedance core.

Another such core comprises a first partial core which consists of rings of hot-rolled iron sheet containing 4.3 to 4.5% silicon, and a second partial core which consists of a ferrite material composed of 47.55 mole Fe O 31.6 mole ZnO, 20.6 mole MO, and 0.25 mole C00, and wherein the first partial core accounts for 65 to 85 percent, preferably 67 percent, of the cross-section of the impedance core.

For the required consumption of about 500 watts, an efficient dimensioning of the impedance core includes the outer diameter of the ferrite ring core and the outer diameter of the rings of the iron sheet containing silicon is 34mm, the inner diameter of the ferrite ring core and the inner diameter of the rings of the iron sheet containing silicon is 20mm, the height ofthe ferrite ring core is 3mm and the sheet thickness of the rings of the iron sheet containing silicon is 0.35mm.

Particularly small dimensions of the suppression component are obtained in connection with a capacitor of 0.1 microfarad by means of a radio interference elimination choke comprising a winding of two layers, at the most, applied to a cup having the impedance core therein, wherein at the beginning of the second layer, the direction of the winding, but not the sense of the winding, is reversed. This type of winding advantageously reduces the influence of the inherent capacity of the coil so that inherent resonances are avoided in the frequency range to be attenuated (KW-range), which resonances otherwise occur in the conventional overwinding of the start of the coil.

' The appliances which may utilize interference elimination are used, among other places, in residences and- 3 lo'r offices where as silent as' possible' an operation of the arrangementis desired. Noise attenuation of the impedance core is accomplished by .pouringout in an insulating, cup a pourable resin which remains elastic, and which comprises, for better heat conductivity, about 40 percent quartz meal. The addition of quartz meal to the pouring resin also offers the advantage of a considerable reduction in cost. For the uniform distribution of the pouring resin in the cup, and to favor its penetration between the rings of the transformer sheets and the individual partial cores, it is advantageous for the annular cup to include lamella-like elevations which project from its inner wallsso that the impedance core does not adhere beyond these projections to the side wall of the cup. in order to make a distribution of the poured resin possible above the bottom of the cup, it is also advantageous to provide elevations at the bottom of the cup which expose an aisle or passageway therebetween so that the impedancecore adheres to the elevations and the pouring resin can spread throughout the entire cup by wayof the passageway.

BRIEFIDESCRIPTION OF THE DRAWING Otherobjects,'features and advantages of the invention, its organization, construction and operationwill best be understood from the following detailed description taken in conjunction with'the accompanying drawings, on which:'

'* 'FlG. Us a sectional elevational view of a radio interference eliminationch'oke constructed inaccordance with the principles of the present inventionyand FIG. 2 is'an electrical's'chematic diagram partic ularly showing the winding of thechoke of FIG. 1.

. oescair'riou OF THE PREFERRED EMBODIMENT In the single figure of the drawing, an impedance core 1 is illustrated as comprising a partial core 2 which includes 17 rings of a cold-rolled iron sheet containing about 3% silicon, and having a sheet thickness of gauge of about 0.35mm, and a partial core 3 of ferrite mate rial composed of 47.55 mole Fe O 31.6.mole

ZnO, 20.6mole NiO, and 0.25m0le C00, which may be produced according to conventional methods. The partial core'3 is 3mm in height so that its effective cross-section accounts for one-third of the effective cross-section of the impedance core 1 and the partial core 2 of iron sheet containing silicon accounts for two-thirds of the effective cross-section of the impe-- dance core 1. The impedance core 1 is placed in a cup 4 which is closed with a cover 7 and adheres or abuts to elevations 5 on the bottom of the cup which are integrally connected to the lamellae 11 at the side walls of the cup 4. As a result of this structure, an aisle or passageway remains between the elevations 5 for passing a poured resin therethrough which remains elastic after hardening. The poured. resin 6-includes about 40 per- '4 Although we. have described our inventionbyreference to a particular construction embodying the principles thereofQmany changes and modifications of our invention may become manifest to those skilled in the art without departing from the spiritand scope of our invention, and it is to be understood that we intend to include within the patent.warranted hereon all such changes and modifications as may reasonably and properly be included within the scope of our contribution to the art.

We claim: 1. A radio interference elimination choke for phase control switching circuits comprising a'magnetic impedance core of two annular axially superposed partial cores, a cup and a cup cover housing said cores, at least one coil carried about said-cup and cupvcover, a first .of said partial cores including iron sheet material containing 2 to 4% Si having high electric losses in the frequency range of 5 to 15 kHz for attenuating transients which are due to impulse-like currents applied to said coil, said first partial core having across section accounting for to percent of the effective cross section of the impedance core, a second of said partial cores including ferrite material having a permeability of at least 200 in the frequency range up tolO MHz, said impedance core exhibiting high-losses due to the effect of the ferrite material in the frequency range of from 10 to 300 MHz with a permeability which decreases with increasing frequency.

2. A radio interference elimination choke according to claim 1, wherein said first partial core comprises rings of a cold-rolled iron sheet containing 2.9 to 3.1% silicon, and said second partial core is composed of 47.55 mole Fe O 3l.6'mole -ZnO ,20.6 mole N.i0 and 0.25 mole C00, I

3. A radio interference elimination choke according to claim 2, wherein said rings of said first partial core contain 3.0% silicon.

4. A radio interference elimination choke according to claim 1, wherein said first partial core comprises rings of a hot-rolled iron sheet containing 4.3 to. 5.5% silicon, and said second partial core is composed of 47.55 mole Fe O 31.6 mole %'ZnO, 20.6 mole MO and 0.25 mole C00. 1

5. A radio interference elimination choke according to claim 1, wherein said partial cores are rings having an outside diameter of 3.4 mm and an inside diameter of 20 mm, said first partial core comprising a plurality of rings having a thickness of 0.35 mm and said second partial core having a height of 3 mm.

6. A radio interference elimination choke according to claim 1, wherein said first partial core accounts for 67 percent of the effective cross section of the impedance core.

7. A radio interference eliminationchoke according to claim 1, wherein said coil comprises superposed windings having a first winding direction and a second winding direction opposite in direction, but not sense, with respect to the first winding direction.

8. A radio interference elimination choke according to claim 1, comprising an elastic resin disposed between said cup and said impedance core, said resin including about 40% quartz meal for improving the heat conductivity of said impedance core.

9. A radio interference elimination choke according to claim 8, wherein said cup includes inwardly directed 6 lamella-like projections extending from its inner walls bottom of said cup which define a passageway for the to space said impedance core from said inner walls. flow of resin through said cup, said impedance core 10. A radio interference elimination choke according carried on said projections. to claim 9, comprising projections extending from the 

1. A radio interference elimination choke for phase control switching circuits comprising a magnetic impedance core of two annular axially superposed partial cores, a cup and a cup cover housing said cores, at least one coil carried about said cup and cup cover, a first of said partial cores including iron sheet material containing 2 to 4% Si having high electric losses in the frequency range of 5 to 15 kHz for attenuating transients which are due to impulse-like currents applied to said coil, said first partial core having a cross section accounting for 65 to 85 percent of the effective cross section of the impedance core, a second of said partial cores including ferrite material having a permeability of at least 200 in the frequency range up to 10 MHz, said impedance core exhibiting high losses due to the effect of the ferrite material in the frequency range of from 10 to 300 MHz with a permeability which decreases with increasing frequency.
 2. A radio interference elimination choke according to claim 1, wherein said first partial core comprises rings of a cold-rolled iron sheet containing 2.9 to 3.1% silicon, and said second partial core is composed of 47.55 mole % Fe2O3, 31.6 mole % ZnO, 20.6 mole % NiO and 0.25 mole % CoO.
 3. A radio interference elimination choke according to claim 2, wherein said rings of said first partial core contain 3.0% silicon.
 4. A radio interference elimination choke according to claim 1, wherein said first partial core comprises rings of a hot-rolled iron sheet containing 4.3 to 5.5% silicon, and said second partial core is composed of 47.55 mole % Fe2O3, 31.6 mole % ZnO, 20.6 mole % NiO and 0.25 mole % CoO.
 5. A radio interference elimination choke according to claim 1, wherein said partial cores are rings having an outside diameter of 34 mm and an inside diameter of 20 mm, said first partial core comprising a plurality of rings having a thickness of 0.35 mm and said second partial core having a height of 3 mm.
 6. A radio interference elimination choke according to claim 1, wherein said first partial core accounts for 67 percent of the effective cross section of the impedance core.
 7. A radio interference elimination choke according to claim 1, wherein said coil comprises superposed windings having a first winding direction and a second winding direction opposite in direction, but not sense, with respect to the first winding direction.
 8. A radio interference elimination choke according to claim 1, comprising an elastic resin disposed between said cup and said impedance core, said resin including about 40% quartz meal for improving the heat conductivity of said impedance core.
 9. A radio interference elimination choke according to claim 8, wherein said cup includes inwardly directed lamella-like projections extending from its inner walls to space said impedance core from said inner walls.
 10. A radio interference elimination choke according to claim 9, comprising projections extending from the bottom of said cup which define a passageway for the flow of resin through said cup, said impedance core carried on said projections. 